Can't Select Warpzone's Patch mesh

I want to color code some of my warpzones with some effects.
Earlier I made a simple patch mesh which made a 2d plane in front of the warpzone, and placed the effect texture in front of it. It colors the warpzone the way I want it to, however nothing can pass through any of the colored warpzones, and I assume that they have a collision set that I should turn off.

Problem is, I can't select them, and when I try to select the patch mesh on the warpzone, I click the warpzone itself or a neighboring brush.

PIc is my warpzone and its patch mesh.
The clip brush is to block players, but allow weapon fire through.

Patch meshes are effectively a single face, so you only need to SHIFT+Click them to select them. If it's still selecting the underlying brush (maybe it's too close?), you can just press H to hide the brush, and SHIFT+H to restore it.

Patch meshes can only be selected from one side, the side the face normal is pointing. In your case this means it can only be selected from the top and not the bottom.

You see the mesh from the bottom because this warpzone-shader is drawn this way (it is not culled) by a special shader-keyword. You can make your life easier by using a very thin brush (1 unit thick) instead of a patch mesh.

Thanks. That explains a lot.